Vibration and noise in pediatric emergency transport vehicles: a potential cause of morbidity?

BACKGROUND: Noise and vibration are stressors that may adversely affect the well-being of infants and children being transported between facilities. Although the problem has been recognized, little has been done to rectify the situation.

HYPOTHESIS: That noise levels in transport incubators during use in transport vehicles exceed the recommended standards, and that vibration levels exceed those that are "very uncomfortable" for healthy adults.

METHODS: We measured noise and vibration (n/v) levels inside and outside a neonatal transport incubator in seven transport vehicles (land, air, and water), and calculated maximum and average, weighted and unweighted levels.

RESULTS: The maximum and average unweighted noise levels in all but one vehicle were over 99 dB. The incubator amplified noise at the lower frequencies (The Canadian Standards Association 1992 recommendation is that the noise level in transport incubators not exceed 60 dBA). The maximum vibration levels ranged from 0.86 m.S-2 to 2.35 m.S-2, and the average levels ranged from 0.33 m.S-2 to 1.46 m.S-2. (Vibration in excess of 1.5 is considered "very uncomfortable," and in excess of 2.0 is "extremely uncomfortable" for healthy adults.)

CONCLUSIONS: Noise and vibration levels inside transport incubators in our most-commonly used transport vehicles often exceed the recommended limits. For neurologically immature and/or physiologically compromised infants and children, current levels of n/v in transport vehicles are too high, and could affect patient morbidity. These n/v levels require further study, and modification of equipment, primarily the incubators, is overdue.